package com.dycong.common.leetcode.yi;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: yilin
 * Date: 2019-08-08
 * Time: 17:34
 */
public class LinkListRecycle {

    public static boolean hasCycle(ListNode head) {
        if (head == null || head.next == null) {
            return false;
        }
        ListNode slow = head;
        ListNode fast = head.next;

        while (slow != fast) {
            if (fast == null || fast.next == null) {
                return false;
            }
            slow = slow.next;
            fast = fast.next.next;

        }
        return true;
    }


    static class ListNode {
        int val;
        ListNode next;

        ListNode(int x) {
            val = x;
        }
    }

}
